It would not necessarily mean more purchases. For the majority of those translations which you suggest, there would literally be zero purchases, because the demand is non-existant.

For the books I would personally most like to translate, I think the problem is marketability. Nordic children's/youth literature often contains nudity/sexuality and/or darker emotional themes which are often viewed as inappropriate in English-speaking cultures.

In "Vi skulle vært løver" by Line Baugstø a young girl discovers her classmate is transgender, and for much of the book participates in transphobia before learning better and supporting her new friend. It's a very well-told and realistic emotional experience, but would likely be seen as grooming by many English-speaking audiences. Not only does it support trans people, but it also spends quite a lot of time in the girls' locker room. I think if you tried to give this to kids in the US or UK there'd just be a ton of controversy about it and it'd get banned.